A simple test called the ankle brachial
index (ABI) can help predict future walking problems in patients
with peripheral arterial disease, a condition that involves hardening
of the blood vessels in the legs and elsewhere, new research shows.

The ABI, which can be determined
in just a few minutes with standard equipment, is the ratio of
the blood pressure in the ankle to the pressure in the arm. Any
value below 1 is considered abnormal and values below 0.25 indicate
severe blood flow problems that could result in amputation of
the leg if left untreated.

Previous reports have shown that
the ABI and leg symptoms correlate with a person's current walking
status. However, it was unclear whether these parameters could
be used to gauge future functional impairment.

To investigate, Dr. Mary McGrae
McDermott, from Northwestern University Feinberg School of Medicine
in Chicago, and colleagues evaluated the outcomes of 676 subjects
who had walking tests performed when the study began and 1 to
2 years later. Of the participants, 417 had peripheral arterial
disease and 259 did not.

The ABI, coupled with leg symptoms,
predicted how far and how fast patients with artery disease would
be able to walk in the coming years. Compared with subjects without
artery disease, patients with persistent leg pain experienced
greater annual declines in walking distance and speed.

Even in the absence of symptoms,
peripheral artery disease was associated with an increased risk
for becoming unable to walk continuously for 6 minutes.

"Our findings underscore the importance
of using the ABI to identify persons with peripheral arterial
disease, since (it) is frequently undiagnosed " or symptomless,
the authors note.